I haven’t tried it myself, the Tydlig app. But, according to Tydligapp.com:

Tydlig is a revolutionary new kind of calculator for iPad and iPhone that sheds the legacy limitations of old devices, for a truly modern experience.

Why do most iOS calculators look like someone taped an old plastic calculator to the screen? How come calculator apps still have buttons like MC/MR/M+/M- when there is enough room on modern devices to store all numbers you could ever think of?

Tydlig starts with a clean sheet, then by only adding interface components that truly makes sense on iPhone and iPad it lets you focus on what really matters: your calculations.